The nuclear anti-ship missile
Per MT and High Guard, a nuclear missile delivers 25,000 "megawatts" times their factor to a black globe. The single TL7 missile is factor 1; the TL13 missile is factor 2. Assuming at least half the blast radiates to space, and assuming that's a megawatt-second, that's 50,000 megajoules - at 4.184×109 joules to the TNT "ton" of blast, only about a 12 ton blast, 0.012 Kt, for the TL 7. One could argue for the blast occurring farther out, more of it going to space, but that only goes so far - and it seems like a waste of a good superweapon.
More likely it's about the size and power of a Davy Crockett, a Korean War era nuclear artillery warhead with a 10 or 20 ton yield, about the smallest fission warhead that could be built with plutonium. Davy Crockett was a 10.75" diameter spherical implosion device with a nose cone containing a contact fuse and a tail section containing a "Safe-Arm" and electronics module with a time fuse. Overall it was 10.75 inches in diameter and about 15.7 inches long, and it weighed 23 kg, which makes it a good candidate for the model for the standard nuke missile warhead.
Incidentally, 50,000 megajoules - at 340 kJ/mol heat of vaporization and 55.845 grams to the mol for iron, that's sufficient energy to vaporize about 8200 kg of iron - a bit over a cubic meter. If we make the (admittedly rather big) assumption that bonded superdense takes about 9 times as much energy to vaporize (using the - again rather big - assumption that soft steel is similar to iron in vaporization point and that bonded superdense is 1/9 the mass for the same strength), that's about 900 kg of bonded superdense. Bonded superdense runs 15 tons to the cubic meter, about 0.06 cubic meters or 60 liters: a crater about 30 cm in radius. Almost 3 times that radius would be liquified, but I'm not up to figuring a mixed blast vaporizing some and liquifying some.
Suffice to say it is quite enough to leave a good-size hole in the hull of the typical armor-40 ship and to send the flash-boiled 900-ish kg 60-ish liter bit of armor blasting into the ship's interior to fry the compartment on the other side and do the damage that shows up in the damage table. It'd take something well north of an armor factor of 62 to keep it from penetrating the hull.
A scientist and his assistant walk into a bar.
The scientist says, "I'll have some H2O."
The assistant says, "I'll have some H2O too."
The assistant dies.